Answer:
solid, ventilated, peaked
Explanation:
Tray covers are available for all classes of tray. They should be installed where falling objects may damage cables or where vertical tray run is accessible by pedestrian or vehicular traffic..
Solid Covers are used for cables with limited heat.
Ventilated covers are available to allow heat produced by cables to dissipate.
Peaked covers are available to reduce pooling of liquids on the cover.